We all know rss like a subscription system to get updates on posted items on blogs or new items on different websites. Now Vista will bring rss to the next level, the new integration in IE 7 is only a small piece of the rss suite. The rss team is bringing new and exciting features to rss, like there are calender sharing, image rss and the new list feeds. The later are rss feeds where items of the feed get updated instead of added, with this kind of list "top 10" lists are possible. The extension for rss is called Microsoft Simple List Extensions.
The rss team has a video where the team explains what's it all about and some samples of how it works, really cool and exciting stuff. In a few lines it comes to this, the complete stuff of reading and parsing rss feeds is left over to the system, also there is a store-and-sync engine which synchronizes the feeds and stores them. This makes it easy for developers to use rss feeds in their applications without having to know the complete standard.
Check also the article on MSDN, it gives you a general overview of the rss support in Vista.
Can't wait to get my hands on this.